Intercellular Communication Between Sertoli Cell and Leydig Cell

在本研究中，我们证明了在未成熟的大鼠Setoli细胞培养的废液中存在一种刺激成熟的小鼠睾丸间质细胞产生睾酮的因子，并显示了该因子的一些新的生化特性。15个浓度的大鼠SCCM以剂量依赖的方式刺激睾酮的产生，从25-50个单位。在100-100毫升剂量时，活性进入平台期。截留分子量为10 kDa的透析膜和超滤膜均能保持间质细胞的刺激活性。然而，在60℃加热30min，活性降低，在37℃与0.1%的胰酶孵育1h后，活性丧失。15倍浓缩的SCCM制剂经TSK G3000 Sw凝胶过滤后，显示出约13 kDa的活性。黄体生成素和SCCM均显着增加细胞外cAMP水平，提示SCCM的腺苷环化酶激活活性。我们检测了从孕烯醇酮到睾酮的DELTA4途径的酶活性。在黄体生成素的急性刺激下，从孕烯醇酮到睾酮的一系列酶的变化不明显，但睾酮的产生却比对照高出好几倍。用SCCM治疗，尽管睾酮的产生增加了，但结果是相同的。我们的SCCM制剂在与最大刺激量的黄体生成素(10IU/ml)孵育时，未能表现出刺激间质细胞睾酮产生的活性。

In the present study, we demonstrate the existence of a factor which stimulates testosterone production by mature mouse Leydig cells in a spent medium of immature rat Setoli cell cultures and show some new biochemical characteristics of this factor.Using ultrafiltration apparatus with a molecular weight cut off of 10 kDa, Sertoli cell conditioned medium SCCM was concentrated. Fifteentimes concentrated rat SCCM stimulated testosterone production in a dose dependent fashion from 25 mul up to 50 mul. The activity came to a plateau at a dose of 100 mul. Leydig cell stimulating activity was retained by both a dialysis membrane and an ultrafiltration membrane with a molecular weight cut off of 10 kDa. However, activity was reduced by heating for 30 min at 60 C and lost after incubation with 0.1% trypsin for 1 h at 37 C.The activity was not retained by a Con A-agarose column and was demonstrated only in break-through fractions. HPLC gel filtration of 15 times concentrated SCCM preparation on TSK gel G3000 SW revealed activity at about 13 kDa. Both LH and SCCM significantly increased extracellular cAMP levels suggesting the activity of adenylcyclase activation of SCCM.We checked the enzyme activities of DELTA4 pathway from pregnenolone to testosterone. With the acute stimulation of LH,no change on the series of enzyme from pregnenolone to testosterone was revealed although testosterone production was stimulated to several times higher than the control. With SCCM treatment, same results were obtained although testosterone production was increased. Our SCCM preparation failed to show the activity stimulating Leydig cell testosterone production when incubated with a maximally stimulating dose of LH (10 IU/ml).